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Biology subjects

Wing, P. A. C.

Publications and source records attributed to Wing, P. A. C..

3 recordsLinked to original sources

XRN1-dependent RNA homeostasis regulates hepatitis D virus

Hepatitis delta virus (HDV) infection causes the most severe form of viral hepatitis, yet the host mechanisms restricting HDV replication remain poorly understood. Although HDV infection activates the MDA5-LGP2 pathway and induces robust interferon (IFN) responses, these antiviral programs have limited impact on viral replication. Here we identify the 5-3 exoribonuclease XRN1 as a key regulator of HDV infection. Loss of XRN1 in hepatoma cells increased double-stranded RNA (dsRNA) levels and induced interferon-stimulated genes (ISGs), including MDA5 and MAVS, and limited HDV infection. XRN1 deficiency enhanced ADAR1-mediated RNA editing, revealing a dynamic interplay between endogenous dsRNA metabolism and antiviral sensing. Inhibition of type I IFN signaling restored MDA5 expression and rescued HDV replication in XRN1-deficient cells. To identify the downstream effectors responsible for this restriction, we combined transcriptomic profiling with functional siRNA screening and identified DUSP5 and SIRPA as previously unrecognized ISGs with anti-HDV activity. Together, our findings establish XRN1 as a gatekeeper of dsRNA homeostasis that controls HDV replication through innate immune activation and reveals host antiviral effectors that may provide therapeutic opportunities for chronic hepatitis D.

molecular biology↗

PreS1-decorated recombinant adenovirus encoding HBV antigens generates neutralizing humoral and cellular immunity

Background & AimsAchieving functional cure for chronic hepatitis B (CHB) will likely require a combinatorial approach targeting multiple aspects of the complex hepatitis B virus (HBV) life cycle and host adaptive immune responses. Here, we developed a therapeutic vaccination strategy targeting the PreS1 region of L-HBsAg, required for cellular entry of both hepatitis B and D viruses. An established potent T-cell inducing platform, recombinant adenovirus (Ad), was used as a nanoparticle scaffold for PreS1 attachment, to generate antibodies that neutralize virus entry and to establish T-cell mediated immune control. Approach & ResultsScreening a cohort of 61 patients diagnosed with CHB revealed minimal evidence of natural anti-PreS1 responses. Thus, Ad particles encoding multiple HBV antigens were decorated with PreS1 peptide using DogTag/DogCatcher protein superglue. Mice vaccinated with PreS1-decorated Ad induced robust anti-PreS1 antibody responses that neutralized HBV and HDV infection. In contrast, an undecorated Ad encoding L-HBsAg failed to neutralize HBV, demonstrating that PreS1 decoration was required for potent HBV neutralization. Strong CD8+ and CD4+ T-cell responses were induced against HBV antigens encoded in the Ad genome. ConclusionsPreS1-decorated Ad combines immunological HBV and HDV entry inhibition with potent anti-HBV T-cell induction in a single platform, providing a promising addition to current therapeutic strategies against CHB, with particular utility in HBV/HDV co-infection.

bioengineering↗

Hypoxia inducible factors regulate Pneumovirus replication by enhancing innate immune sensing

The immune mechanisms responsible for protection and pathogenesis in pneumoviral infection are not well defined. We demonstrated that pharmacological activation of the hypoxic inducible factor (HIF) signalling axis using Daprodustat limited viral replication through enhanced immune signalling. Transcriptomic analysis revealed HIF augmented activation of innate immune response genes, including interferon-stimulated gene 15 (Isg15), in the lung and spleen of mice infected with pneumonia virus of mice (PVM). In human respiratory syncytial virus (hRSV) infected airway epithelial cells, Daprodustat inhibited viral replication and enhanced ISG15 expression in a HIF-dependent manner. Importantly, inhibition of type I interferon signalling or the RIG-I sensing pathway abrogated the antiviral activity of HIF. Moreover, Daprodustat increased interferon signalling in response to viral RNA, suggesting that HIF inhibits pneumovirus replication through enhancing viral RNA sensing. Mechanistically, Daprodustat reduced N6-methyladenosine modification of viral RNA through upregulation of RNA demethylases, promoting detection by innate immune sensors. This study highlights the intricate interplay between hypoxia and antiviral immunity and offers valuable insights into pneumovirus-host interactions and potential therapeutic interventions. SIGNIFICANCE STATEMENTThis study explores the role of the hypoxic inducible factor (HIF) signalling pathway in limiting pneumoviral infections, such as respiratory syncytial virus (hRSV) and pneumonia virus of mice (PVM). Using Daprodustat, a clinically approved activator of HIF signalling we demonstrated that stimulation of this pathway enhanced innate immune signalling and limited viral replication. Transcriptomic analysis showed that HIF promoted innate immune response genes in mice infected with PVM and human airway epithelial cells infected with hRSV. Importantly, inhibition of type I interferon signalling or the RIG-I sensing pathway abrogated the antiviral activity of HIF. We uncovered a role for HIF to regulate the levels of N6-methyladenosine modification of viral RNA transcripts, resulting in the increased activation of nucleic acid sensing.

microbiology↗